A given Fedora release has a much shorter release "half-life" (where you can get package updates) than Centos. Anything older than FC6 has no package updates any longer.

Updates are important when you are exposing services to the Big Bad h4x0r filled intertubes. Otherwise they be in ur servers stealing ur internetz.

Centos is a rebuild of Redhat Enterprise which means it is supported for many years longer than the year+ a month a Fedora release typically gets.

For a "fire and semi-forget" type of operation like an IRLP node or a Dstar gateway or other production server, Centos is perfect.

Operationally you won't notice much of a difference.

You can run "setup" as root and then choose "network configuration" to fix your IP address issues. The DNS servers your system uses are set up in /etc/resolv.conf, which you can change with an editor as root. (real sysadmins use vi)

Redhat has some excellent documentation on their RHEL products located here and naturally the almighty Google is your friend with Linux